In wireless communication, communication error (communication failure) occurs due to noise, interference, attenuation, etc. When a device is being controlled or monitored using wireless communication, it is necessary to take measures to prevent the device from malfunctioning or prevent monitor information from being missed due to communication error. For this reason, retransmission of communication data is often attempted when communication error occurs.
In most cases, a communication frame is generally composed of a physical layer header, an MAC header (hereinafter this expression means physical address-including information) and a data field. There has been known a technique in which this data field is further split into cells so that the cells are subjected to packet transmission after an error checking code is added to each of the cells. Since only the finely split cells need to be retransmitted, lowering of transmission efficiency can be suppressed even if communication error occurs due to noise etc. For example, this technique has been disclosed in JP-A-10-93584.